By: Leah Sylvester and Allison Kodroff

Born September 6, 1766, died July 27, Born in Eaglesfield England Colorblind Just like his older brother

Most of his life a teacher at a Quaker School He moved to another teaching job in Manchester at the New College. Teaching math and philosophy While there, he pursued his interest in meteorology Found research on atmospheric pressure and he published it in his 1 st book.

Also researched color blindness. Since it affected both him and his bother. Created a theory that color blindness was genetic. His theory was proven true. Contributions to the understanding of the re-green color blindness—Daltonism B/c of his interest in atmospheric pressure this lead to a closer look at gases

His theory: Matter can’t be divided into smaller and smaller pieces forever, eventually the smallest possible piece would be obtained. This piece would be indivisible. He named the smallest piece of matter “atomos,” meaning “not to be cut.” Atoms were hard particles made of the same material but different shapes and sizes. Atoms were infinite in number, always moving and capable of joining together.

Used some of Democritus’ theory of matter. Borrowed the term “atom” to label the particles. Created the 1 st chart of atomic weights. Published in his book where he expands on the subject. A New System of Chemical Philosophy introduced belief that atoms of differ elements could be distinguished based on their atomic weight

Law of Multiple Proportions (sometimes called Dalton's Law): If two elements form more than one compound between them, the ratios of the masses of the 2 nd element combined with the mass of the 1 st element will be ratios of small whole numbers.

Elements are made of extremely small particles called atoms. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.

Atoms cannot be subdivided, created, or destroyed. Atoms of different elements combine in simple whole- number ratios to form chemical compounds. In chemical reactions, atoms are combined, separated, or rearranged. Five Main Points of Dalton's Atomic Theory

Dalton’s atomic theory was not all correct… Dalton thought atoms were indivisible  atoms are divisible Atoms of a given element have identical properties  atoms of the same element have slightly different masses A chemical reaction to rearrange atoms  atoms can only be destroyed by chemical reactions

ion/dalton.html ion/dalton.html Chemistry Matter and Change